The first edition of Drawing the Line was based entirely on my own research and experiences. It was not until two years after publication that I discovered there was an entire tribe of American surveyors who dedicated all their spare energies to recording, collating, maintaining, researching, and in all ways preserving the famous Mason–Dixon Line.

It would be a long list to mention everybody to whom I owe thanks, but in particular I must acknowledge, in no particular order, the Professional Land Surveyors Charles Langelan of the Surveyors’ Historical Society, whose enthusiasm knows no bounds; Todd Babcock and Jim Shomper, heroes of the Mason–Dixon Line Preservation Partnership; Milton Denny and David Lee Ingram, experts in early surveying methods; and David Thaler, whose research identified the fate of Mason and Dixon’s transit instrument.

Grateful thanks also to Kate Roby, owner of Stargazers Farm, who so generously shared her research of the house that Mason and Dixon made their home-from-home; Jonathon Peacock, who so kindly shared his remarkable research into the life and times of Jeremiah Dixon; George Dixon (a distant relation of Jeremiah), a man of extraordinary warmth and generosity; Tony Pawlyn, Head of Library, National Maritime Museum, Cornwall, whose painstaking research proved invaluable in solving some of the maritime mysteries; and Allen C. Browne for generously providing excellent photos of some of the stones.

Finally, special thanks to my wife and soul-mate, Linda, who with perseverance put right all my wrongs, made countless improvements, demanded explanations, and generally kept me focused; and to Peter Coveney and all the staff at Wiley for their faith, support, and patience without which none of this could have happened.

In the fifteen years since Drawing the Line was first published, interest in Mason, Dixon, and their famous Line has blossomed. The first edition was written based entirely on my own research and experiences as a land surveyor. It was not until two years after the book came out that I discovered there was a group of American surveyors who dedicated all their spare energies to preserving the Mason–Dixon Line, leading to new discoveries and solving some of the more intriguing enigmas.

It is a sad fact that there are no known images of either Mason or Dixon. Charles Mason had a large family, six boys and two girls, but so far no trace of his descendents, either in Britain or in America, where Mason settled shortly before his death, has come to light. All that can be said is that, in the Mason family, Charles appears to have been a scientific one-off. Jeremiah Dixon’s family, on the other hand, is still extant, and have been very generous in sharing information on their famous surveying ancestor. The Dixons were, and are, a talented family – Jeremiah’s brother George is credited as the first to use coal gas as a source of illumination. The family also sired some outstanding engineers, among whom were John Dixon and his brother Waynman, who brought Cleopatra’s Needle to London from Egypt.

For some six years, Mason and Dixon worked together as a team, and most likely remained in contact until Dixon’s death in 1779. It can only be concluded from their long and close association that they got on well, but what sort of relationship they enjoyed is unknown. What can be said is that their partnership marked a unique union of land surveying with positional astronomy, creating, perhaps for the first time, what we call today the geodetic surveyor.

The genesis for the first edition of Drawing the Line came in 1976 on the eve of my departure to set up a survey company in Tehran, Iran. Over a farewell pint of beer, an old surveyor friend posed the question: how would a surveyor run a 230-mile line of constant latitude? He was referring, of course, to Mason and Dixon’s famous border line; at the time, I had never heard of it. But it was an interesting question, and one that taxed my brain a few years later when I had to run a twenty-kilometer line of latitude in Scotland. However, any interest I had in learning something of the history of the Mason–Dixon Line was thwarted by a dearth of information, that is, until I discovered a copy of Nelson Beecher Keyes’ 1954 edition of The American Frontier in a second-hand book shop in New Orleans; in it were half a dozen pages about the Line.

A copy of Hughlett Mason’s 1969 transcription of Mason’s journal, courtesy of the British library system, and a set of the excellent research papers written by the physicist Thomas D. Cope between 1939 and 1956, provided the foundations for starting the serious business of researching the book.

“It’s just pages and pages of gobbledygook,” so said a friend when I proudly showed him Mason’s journal, but the endless lists of astronomical observations and surveying hieroglyphics spoke volumes to one who has spent many a chilly night taking star shots and wrestling with almanacs and log tables in the dim light of a hurricane lamp in the days before GPS. Of course, the Mason–Dixon Line is much more than a border between states, and in an effort to gauge its meaning today I used my spare time during frequent visits to the United States to ask ordinary Americans what it meant to them. Perhaps half of the fifty or so persons I asked knew the Line was something to do with the division between North and South and with slavery, but of the two men themselves, very few had any idea.

It was to fill the gaps and renew interest in the Mason–Dixon Line, and specifically to explain how they completed such a monumental feat, that I wrote Drawing the Line. This revised edition has been updated with all the latest research, and includes a comprehensive bibliography and a fully revised appendix to explain the more technical aspects of the work. I have also included a brief history of Earth measuring and short discussion on a theory of why colonial American miles, including Mason and Dixon’s mile, were longer than contemporary British miles.

For simplicity, British monarchy is referenced as kings or queens of England. After the accession of James I of England (James V of Scotland) until the Act of Union, monarchs carried two regnal numbers as related to England and to Scotland. After the 1707 Act of Union the regnal number for Scotland was less frequent used. Following the union with the kingdom of Ireland in 1801, the collective term for England, Wales and Scotland as Great Britain, became the United Kingdom of Great Britain and Ireland until Irish independence in 1922.

Their names were Charles Mason and Jeremiah Dixon. And they were the last best hope for peace. But little did they know what started as a mere border dispute would come to mark the greatest divide in American history.

Later in history, their names would become irrevocably linked with the boundary itself: the Mason–Dixon Line, best remembered today as the symbolic Civil War divide between North and South, the partition between slave and free states. In human terms, the Mason–Dixon Line was the eighteenth century’s most ambitious border survey, a perfect curve of latitude, two hundred forty-five miles from end to end.

The long war with France was over, but the costs had crippled the Exchequer. In London, the new Prime Minister was the unpopular Sir George Grenville, intent on reducing the war debt, and meeting the rising costs of maintaining the army in North America, by taxing the colonies. He was also rumored to be planning restrictions on settlement west of the Alleghenies to appease the restless Indians. In the frontier lands, far to the west, there was serious trouble and reports of massacres.

Seventeen sixty-three was the year when every ship from England brought news of another tax or more stifling regulations to the American colonists, but for the small cluster of people gathered on the river quay at Marcus Hook, there was at least some good news. The Hanover Packet had just berthed with a cargo from England, and London merchants with an eye to business. Among the fifteen or so passengers disembarking that gray November day were the two young Englishmen, recently engaged by the landowners who held the royal grants, the so-called proprietors of Maryland and Pennsylvania. Their appointment had been a secret, a last-ditch attempt at ending eighty years of acrimony, bloodshed, and war. The men who finally solved the contentious border were not lawyers or politicians, but astronomers; men of science.

In the Age of Enlightenment, when intellectuals across Europe and in North America were embracing reason, logic, and the concepts of civil freedom, where mathematicians and astronomers were beginning to make sense of the natural world, so religion and politics tried pulling it apart.

In the seventeenth century, the new English lords of America owed their good fortunes as much to their religious affiliations as they did to their enormous wealth. Tensions between Catholic and Protestant interests waxed and waned throughout the period as monarch succeeded monarch. Towards the end of the century, the Dutch Prince William of Orange became king and finally established in England the supremacy of Protestantism and Parliament, and the modern era began. British America grew apace as settlers poured into the territories, and vast new trading patterns emerged. Colonial expansion outpaced the political processes and when Mason and Dixon stepped ashore in America in the gray chill of a November day, the land they found was substantially different from the one they expected.

In England, most people, and certainly most members of Parliament, regarded the North American colonies as if they were distant English shires. Unlike their English counterparts, qualifying colonists had neither the vote nor representation in Parliament. Discontent and anger were growing towards the way the British government, and especially King George III, was running American affairs.

At the time, the British Empire as such did not exist and the nineteenth-century plantation regime, with its exceptional brutality, was still in its infancy. To be sure, there were slaves in America, perhaps as many as a million, but not all the enslaved were black. The colonial broadsheets of the time contained almost as many advertisements requesting the apprehension of transported white convicts and indentured servants as they did for African runaways. Even so, the overwhelming majority of slaves were kidnapped West African natives and their progeny. In 1750, the African Company of Merchants, the last major London company engaged in the nefarious trade, began slaving out of Bristol. Also known as the Merchants Trading to Africa Company, it was the direct successor of the Company of Royal Adventurers Trading to Africa founded by James Stuart, Duke of York, later the despised King James II. Slaving was big business. In the year Mason and Dixon voyaged to America, the slave trade was at its height, with more than one hundred fifty ships transporting forty-five thousand Africans annually across the Atlantic to the American colonies, the majority ending up in the middle and southern provinces; by 1763, nearly forty percent of Maryland’s population, working the tobacco fields, were forced labor.

Although at its peak in the colonies, slavery was becoming morally unacceptable, at least in England. In 1772, Lord Chief Justice William Murray, the Earl Mansfield, presided over the case of James Somersett, a fugitive Virginian slave who had escaped to England. In Somerset v. Stewart (1772) Lord Mansfield, whose decisions reflected the morals of the Enlightenment, ruled that:

The state of slavery is . . . so odious, that nothing can be suffered to support it, but positive law. Whatever inconveniences, therefore, may follow from the decision, I cannot say this case is allowed or approved by the law of England; and therefore [Somersett] must be discharged.¹

No longer could a slave be repatriated forcibly to face retributive punishment at the hand of his master. The poet William Cowper was moved to write:

We have no slaves at home – Then why abroad?

And they themselves, once ferried o’er the wave

That parts us, are emancipate, and loos’d

Slaves cannot breathe in England; if their lungs

Receive our air, that moment they are free;

They touch our country, and their shackles fall.²

Within ten years of Murray’s judgment, the beginning of the true abolitionist movement was underway. However, all that lay in the future. During Mason and Dixon’s travels in America, slaves doing sweat labor in the fields would have been a familiar sight.

Apart from the imported slaves, there were also the indigenous American natives. Neither races were properly understood. Natural ignorance, perverted scripture, and fear led to bigotry and atrocity, and in this respect the settlers of British America were not unique. To understand the America of Charles Mason and Jeremiah Dixon, one has to cast away contemporary ideas of freedom and one-man-one-vote; there was no vote for the half million emigrants who flooded annually into the coastal provinces. Their moral yardsticks they imported from the Old World, refashioned for a new world where men and women were carving a new land from the wilderness. It was a world where bravery and strength of spirit went hand in hand with the hardships of everyday life in an untamed environment. Such conditions forged a fierce pride which, melded with the radical waves of the Enlightenment, evolved into an article of faith. As an American friend once observed: “in the United States, freedom is mandatory and requires an excessive degree of expression.” In Europe, these ideas and values were to develop more slowly and more cautiously.

The fragile peace that followed the end of the French and Indian War in 1763 was a time of transition that would ultimately lead to the transformation of the colonists from European vassals into American citizens. It was the era of the two Georges; George III and George Washington. To quote the 1851 edition of Charles Dickens’ A Child’s History of England:

It was in the reign of George the Third that England lost North America, by persisting in taxing her without her own consent. That immense country, made independent under WASHINGTON, and left to itself, became the United States; one of the greatest nations of the earth.

Ten years after Dickens wrote those words, the slaves in the cotton and tobacco fields had helped generate enough wealth to fund the most awful of civil wars, where the Mason–Dixon Line took on a darker, more sinister meaning.